sphinxtogithub: add support for Sphinx 7.2.0

Newer versions of sphinx use a pathlib.Path object instead
of a string for the "root" parameter. Add compatibility
by stringifying the value provided by Sphinx.

See-also: sphinx-doc/sphinx#11526
See-also: sphinx-doc/sphinx#11608
See-also: git-cola/git-cola#1336
Original-patch-by: Martin Gysel <me@bearsh.org>

sphinxtogithub/sphinxtogithub.py

@@ -107,7 +107,7 @@ def __init__(self, name, root, renamer):
 
         self.name = name
         self.new_name = name[1:]
-        self.root = root + os.sep
+        self.root = str(root) + os.sep
         self.renamer = renamer
 
     def path(self):